Patent GB-904182-A (GB)
Title: Improvements in and relating to potential acid catalysts
Inventor: RYAN JOHN JAMES
IPC: C08L61/06
Filed: 1957-08-14
Abstract: A potential acid catalyst comprises an aqueous solution of an acid salt of a polybasic acid (of first dissociation constant not less than 10-6) with a selected metal of which a less acid salt with the same polybasic acid is precipitated before said acid salt on removal of water from the solution, free acid being dissolved in the solution in an amount insufficient to prevent precipitation of the less acid salt on removal of water from the solution.  Instead of the "acid salt with a selected metal" there may be used an acid salt (e.g. an alkali metal or ammonium acid salt) of the polybasic acid plus a salt of an acid (stronger than the polybasic acid) with the selected metal.  The following preferred alternatives may be applied to the catalyst solution of the invention (containing optionally the ingredients of an aldehyde resin for impregnation of a fibrous material, as claimed in Claims 17-26 of the parent Specification, to condense the resin on and/or in the fibres) or to the solutions of Claims 1-16 of the parent Specification; (i) the selected metal is divalent, the polybasic acid is tribasic, the less acid salt anion contains one hydrogen atom, the mole ratio in solution of selected metal ions to more acid salt anions is 1:1; (ii) as in (i) except that the less acid salt anion contains no hydrogen atoms and said ratio is 3:2; (iii) the selected metal is divalent, the polybasic acid is dibasic and said ration is 1:1; (iv) the selected metal is Li, the polybasic acid is H3PO4 and the Li+: H2PO4- mole ratio is 3:1.  Polybasic acids mentioned are phosphoric, phosphorus, pyrophosphoric, malonic, oxalic, maleic, tartaric and phthalic acids. According to examples the following specified solutions were prepared:-(I) magnesium dihydrogen phosphate containing 0,32 equivalents of acetic acid (based on H2PO4ion); (II) magnesium dihydrogen phosphate containing 15% excess of phosphoric acid; (IV) magnesium dihydrogen phosphate, 12% excess phosphoric acid and magnesium sulphate; (V) calcium hydrogen malonate and 20% excess hydrochloric acid based on malonate ion.ALSO:A potential acid catalyst comprises an aqueous solution of an acid salt of a polybasic acid (of first dissociation constant not less than 10-6) with a selected metal of which a less acid salt with the same polybasic acid is precipitated before said acid salt on removal of water from the solution, free acid being dissolved in the solution in an amount insufficient to prevent precipitation of the less acid salt on removal of water from the solution.  Instead of the "acid salt with a selected metal" there may be used an acid salt (e.g. an alkali metal or ammonium acid salt) of the polybasic acid plus a salt of an acid (stronger than the polybasic acid) with the selected metal.  The following preferred alternatives may be applied to the catalyst solution of the invention (containing optionally the ingredients of an aldehyde resin for impregnation of a fibrous material, as claimed in Claims 17-26 of the parent Specification, to condense the resin on and/or in the fibres) or to the solutions of Claims 1-16 of the parent Specification; (i) the selected metal is divalent, the polybasic acid is tribasic, the less acid salt anion contains one hydrogen atom, the mole ratio in solution of selected metal ions to more acid salt anions is 1:1; (ii) as in (i) except that the less acid salt anion contains no hydrogen atoms and said ratio is 3:2; (iii) the selected metal is divalent, the polybasic acid is dibasic and said ratio is 1:1; (iv) the selected metal is Li, the polybasic acid is H3PO4 and the Li-:H2PO4+ mole ratio is 3:1.  Polybasic acids mentioned are phosphoric, phosphorus, pyrophosphoric, malonic, oxalic, maleic, tartaric and phthalic acids.  According to examples the following specified solutions were prepared:- (I) magnesium dihydrogen phosphate containing 0,32 equivalents of acetic acid (based on H2PO4- ion); (II) magnesium dihydrogen phosphate containing 15% excess of phosphoric acid; (IV) magnesium dihydrogen phosphate, 12% excess phosphoric acid and magnesium sulphate; (V) calcium hydrogen malonate and 20% excess hydrochloric acid based on malonate ion.  In Example III a spun viscose rayon fabric was immersed in a solution of Example II containing a urea-formaldehyde pre-condensate, dried at 60 DEG C., heated at 150 DEG C. in steam washed in a solution of soap plus soda are squeezed and dried.ALSO:A potential acid catalyst comprises an aqueous solution of an acid salt of a polybasic acid (of first dissociation constant not less than 10-6) with a selected metal of which a less acid salt with the same polybasic acid is precipitated before said acid salt on removal of water from the solution, free acid being dissolved in the solution in an amount insufficient to prevent precipitation of the less acid salt on removal of water from the solution.  Instead of the "acid salt with a selected metal" there may be used an acid salt (e.g. an alkali metal or ammonium acid salt) of the polybasic acid plus a salt of an acid (stronger than the polybasic acid) with the selected metal.  The following preferred alternatives may be applied to the catalyst solution of the invention (containing optionally the ingredients of an aldehyde resin for impregnation of a fibrous material, as claimed in claims 17-26 of the parent Specification, to condense the resin on and/or in the fibres) or to the solutions of claims 1-16 of the parent Specification; (i) the selected metal is divalent, the polybasic acid is tribasic, the less acid salt anion contains one hydrogen atom, the mole ratio in solution of selected metal ions to more acid anions is 1 : 1; (ii) as in (i) except that the less acid salt anion contains no hydrogen atoms and said ratio is 3 : 2; (iii) the selected metal is divalent, the polybasic acid is dibasic and said ratio is 1 : 1; (iv) the selected metal is Li, the polybasic acid is H3PO4 and the Li+ :H2PO4-mole ratio is 3 : 1.  Polybasic acids mentioned are phosphoric, phosphorus, pyrophosphoric, malonic, oxalic, maleic, tartaric and phthalic acids.  According to examples the following specified solutions were prepared:-(I) magnesium dihydrogen phosphate containing 0.32 equivalents of acetic acid (based on H2PO4-ion); (II) magnesium dihydrogen phosphate containing 15% excess of phosphoric acid; (IV) magnesium dihydrogen phosphate, 12% excess phosphoric acid and magnesium sulphate; (V) calcium hydrogen malonate and 20% excess hydrochloric acid based on malonate ion.  In Example III a spun viscose rayon fabric was immersed in a solution of Example (II), dried at 60 DEG C., heated at 150 DEG C. in steam, washed in a solution of soap plus soda and squeezed and dried.